March 13, 2009

"A largely ignored issue is how to deal responsibly with the environmental hazards presented by old rotor blades disposed of at the end of their operational lifecycle. ‘The 100,000 wind turbines operational at the end of 2007 contain about 660,000 tonnes of fibre-reinforced plastics, that at some time in the future will end up as a huge chemical waste pile. By 2017 the number of operational turbines worldwide will perhaps have grown to 400,000 units, which corresponds to about 6.6 million tonnes of fibre-reinforced plastics waste. The recycling of steel and non-ferrous metals is a relatively well-known straight-forward process, but this essential know-how is far more limited for fibre-reinforced future plastics waste’, Molly [DEWI (German wind energy institute) managing director Jens Peter Molly] concluded. ...

"Increasing renewable energy systems, while sharing an electric power generation and supply infrastructure, raises the need to develop sufficient energy storage capacity. This is essential to balance fluctuating power feed-in from these inherently variable power sources. Among several options being researched in Northern Germany is adiabatic (no heat exchange) compressed air energy storage in underground salt formations, and especially in naturally formed caverns. These structures, which have an average size of 500,000m3, offer a storage capacity between 2.02–2.73 kWh/m3. Total capacity for adiabatic energy storage in Northern Germany is estimated at 800–2500 GWh. The energy storage efficiency depends on the technology applied and is estimated in the range of 50%–70%. However, there are competing uses for these caverns – underground CO2 capture and the long-term storage of nuclear waste."